Senate Finance Chairman Charles Grassley, R-Iowa, says the FDA gave Merck notice before it let the public know that the popular pain drug was tied to increased risks of heart attack and stroke, CBS News reported.
More than 80 million people used Vioxx worldwide. Merck reported Vioxx sales of $2.5 billion in 2003, the year before it withdrew the drug from the market.
Senior FDA scientist Dr. David Graham, who had flagged Vioxx's heart issues, was told by his superiors to give his report to Merck but keep it from the public, CBS said.
"The FDA officials didn't want to allow me to present my work at a scientific conference, but at the same time they wanted to be sure that Merck had a copy of my scientific presentation," Graham said.
The FDA had no comment. Merck said Graham and others at the FDA separately gave their scientific views to the drug maker, CBS reported.